Acid-reactive fillers have been widely used in dental compositions. Acid-reactive fillers include, for example, metal oxides, metal salts, and glasses. An example of an acid-reactive glass is fluoroaluminosilicate (FAS) glass, which is a known fluoride releasing material. FAS glass particles are typically prepared by a melt fusion process, which effectively limits available particle sizes to particles typically having an average size of at least 0.5 micrometers.
For applications in which the acid-reactive filler is dispersed in a hardenable resin to form a dental composition (e.g., a dental paste), the reactivity of the acid-reactive filler in the composition is generally limited by the available surface area of the acid-reactive filler. Thus, high loadings (e.g., greater than 50% by weight) of acid-reactive filler are often used to achieve compositions with the desired level of reactivity. However, high loadings of acid-reactive fillers sometimes restrict the flexibility to incorporate additional fillers (e.g., non acid-reactive fillers) in the composition.
As such, there remains a need for acid-reactive dental fillers with improved properties including, for example, higher surface areas.